"Avast Free Mobile Security supports a number of features that are usually available only in paid-for Android security software," writes PCWorld's Lucian Constantin. "These include privacy reports, call and SMS filtering, SIM-card change notifications, firewall and application management."

"The antivirus component supports real-time protection and automatic updates," Constantin writes. "Updates can be configured to only be downloaded over certain types of connections and the interface can be protected with a password."